WASHINGTON (AP) — The drugmaker Merck & Co. Inc. has received approval for an updated version of its Gardasil vaccine that protects against an additional five strains of the virus that causes most cases of cervical cancer.

The Food and Drug Administration approved the company’s Gardasil 9, which protects against nine strains of the virus called HPV, or human papillomavirus. That’s up from four strains covered by the original Gardasil vaccine approved in 2006.

The FDA said Wednesday the updated Gardasil has the potential to prevent roughly 90 percent of cervical, vulvar, vaginal and anal cancers. Original Gardasil protected against strains blamed for 70 percent of U.S. cervical cancers. Like its predecessor, Gardasil 9 also guards against two viral strains that cause genital warts.

About 75 to 80 percent of men and women are infected with HPV during their lifetime.  Most don’t develop symptoms and clear it on their own. But some infections lead to genital warts, cervical cancer and other cancers.  

The FDA approved the vaccine for use in males and females — in ages 9 to 26 for females, and 9 to 15 in males. Vaccination requires three shots over 6 months.

Last year a study by the Centers for Disease Control and Prevention found that the vaccine cut viral infections in teen girls by half. The study also showed that only about a third of teen girls had received all three shots. The vaccine was recommended for boys in late 2011.

The shots work best if given before someone is sexually active so public health officials have emphasized giving the vaccine to 11- and 12-year olds.

FDA regulators approved Gardasil 9 based on company studies enrolling 13,000 patients. The most common side effects linked to the vaccine were related to the injection, including pain, swelling and redness.

Kenilworth, New Jersey-based Merck reported Gardasil sales of $1.83 billion in 2013, up from $1.63 billion the year before.